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    SubjectRe: kernel + gcc 4.1 = several problems
    Grzegorz Kulewski wrote:
    > On Wed, 3 Jan 2007, Alan wrote:
    >> The proper fix for all of this mess is to fix the gcc compiler suite to
    >> actually generate i686 code when told to use i686. CMOV is an optional
    >> i686 extension which gcc uses without checking. In early PIV days it made
    >> sense but on modern processors CMOV is so pointless the bug should be
    >> fixed. At that point an i686 kernel would contain i686 instructions and
    >> actually run on all i686 processors ending all the i586 pain for most
    >> users and distributions.
    > Could you explain why CMOV is pointless now? Are there any benchmarks
    > proving that?

    In theory modern processors should have no trouble converting a
    test/move sequence into the same uops generated by a cmov instruction,
    for one.


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      Last update: 2007-01-03 12:57    [W:0.019 / U:1.808 seconds]
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